| | Brewster, NY | Mastic, NY | United States |
| Population | 2,505 | 15,576 | 329,725,481 |
| Female Population | 37.1% | 48.5% | 50.5% |
| Male Population | 62.9% | 51.6% | 49.5% |
| Median Age | 33 | 32.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,410 | 14,485 | 309,327,143 |
| Population - 2000 | 2,162 | 15,436 | 285,036,114 |
| Population - 1990 | 1,566 | 13,778 | 251,960,433 |
| Pop. 2000 to Now | 8.0% | -0.3% | 15.6% |
| Pop. 1990 to Now | 49.0% | 11.7% | 30.8% |
| space4 | | | |
| Population Density | 5,112.2 | 3,990.8 | 93.4 |
| Land Area | 0.5 | 3.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Brewster, NY | Mastic, NY | United States |
| Age 0 to 4 | 4.1% | 6.3% | 5.9% |
| Age 5 to 9 | 10.4% | 6.5% | 6.1% |
| Age 10 to 14 | 3.5% | 7.4% | 6.6% |
| Age 15 to 17 | 1.3% | 5.8% | 3.9% |
| Age 18 to 20 | 5.6% | 5.2% | 4.0% |
| Age 21 to 24 | 6.0% | 7.0% | 5.2% |
| Age 25 to 34 | 25.8% | 16.1% | 13.8% |
| Age 35 to 44 | 17.1% | 11.6% | 12.9% |
| Age 45 to 54 | 11.2% | 12.8% | 12.6% |
| Age 55 to 59 | 1.8% | 5.1% | 6.7% |
| Age 60 to 64 | 2.7% | 6.1% | 6.3% |
| Age 65 to 74 | 6.7% | 8.2% | 9.6% |
| Age 75 to 84 | 3.6% | 1.5% | 4.5% |
| Age 85 and over | 0.3% | 0.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Brewster, NY | Mastic, NY | United States |
| White | 26.2% | 65.0% | 59.4% |
| Black | 0.8% | 7.0% | 12.2% |
| Asian | 0.4% | 0.8% | 5.6% |
| Native American | 0.0% | 0.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 3.2% | 0.0% | 0.4% |
| Two or More Races | 1.4% | 2.5% | 3.2% |
| Hispanic | 68.0% | 23.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Brewster, NY | Mastic, NY | United States |
| Married Population | 46.0% | 41.5% | 49.8% |
| Currently Married | 39.6% | 40.5% | 48.0% |
| Married but Separated | 6.4% | 1.1% | 1.8% |
| Single Population | 54.0% | 58.5% | 50.2% |
| Never Married | 39.1% | 44.2% | 33.8% |
| Divorced | 11.9% | 9.1% | 10.8% |
| Widowed | 3.0% | 5.2% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 3.57 | 2.60 |
| Households | 954 | 4,354 | 124,010,992 |
| Family Households | 542 | 3,661 | 80,755,759 |
| Married couple, w/children | 47.2% | 31.4% | 30.5% |
| Married couple, no children | 19.9% | 33.4% | 42.9% |
| Non Family Households | 412 | 693 | 43,255,233 |
| Single householder, w/children | 19.6% | 20.6% | 15.8% |
| Single householder, no children | 13.3% | 14.6% | 10.8% |